Picture two homes on the same street: one constructed in the 1950s and the other in the 1990s. There are no trees or other shade. The air conditioning units are identical, recently replaced, and operating perfectly. Identical thermostats are set at 82 degrees Fahrenheit (27.8 Celsius).

When it’s 110 F (43.3 C) outside, the 1950s house will likely feel at least 10 F (5.6 C) warmer inside, even with the same air temperature.

Why?

The answer has to do with radiant heat. Radiant heat is what keeps you toasty warm at a campfire on a cold winter night. The fire doesn’t warm the air much; rather, like the Sun, most of the fire’s heat moves through invisible waves directly from the campfire to your body.

In the radiant heat of the Arizona sun, the surface temperature of the uninsulated post-and-beam ceilings in my house, one of 41,000 built in Tucson during the post-World War II era, can reach over 100 F (37.8 C). The single-glazed steel windows register 122 F (50 C), and the uninsulated concrete block walls aren’t much cooler.

Inside my house on triple-digit days, it can feel like I’m standing near a campfire, even with the air conditioner roaring to maintain 75 F (23.9 C). And when the system breaks – as it did during the long-running 2023 heat wave, when Phoenix hit 110 F (43.3 C) every day for weeks – temperatures rise dangerously fast. Without the AC, the hot surfaces plus the swirl of air from the ceiling fan makes the house feel like an air fryer.

Air temperature: An incomplete indicator of comfort

While people are used to thinking about how clothing, air movement, temperature and humidity affect comfort, two lesser-known measures help explain how they experience comfort indoors:

1. Mean radiant temperature. This is the average temperature of all the surfaces that surround us: ceiling, windows, walls, floor. For radiant heat to move between an object and the human body, it needs an uninterrupted line of sight, so ceilings and unobstructed windows have an outsized influence on the radiant temperature experienced in a specific place in a house.

2. Operative temperature. This can be approximated by averaging the mean radiant temperature and the average air temperature in a room. Other calculations of operative temperature take into account effects of air movement, humidity and additional variables. Roughly half of how you experience comfort is determined by the radiant environment.

Unfortunately, as the building scientist Robert Bean (no relation) says, “an entire industry of manufacturers, suppliers, builders and tradespeople incorrectly equate thermal comfort with air temperatures.” The result is that most people are completely oblivious to what actually makes a space feel comfortable — or uncomfortably hot.

On a hot, sunny day, good insulation and double-pane windows slow heat transfer enough for air conditioning to keep the mean radiant temperature inside the building within a few degrees of the air temperature.

However, in an under-insulated building, such as my house, or in some older public housing projects in Phoenix, the high mean radiant temperature can push the operative temperature over 90 F (32.2 C) – even with the thermostat set to 75 F (23.9 C). When the surface temperature exceeds the temperature of our skin, heat will begin to radiate from the hot surface into the body, making heat stroke more likely.

While the exact threshold where overheating becomes dangerous is debated, most people would agree that 90 F (32.2 C) is far too warm for comfort.

Hot surfaces are why smaller buildings, such as mobile homes, tiny homes, shipping containers and garages turned into apartments, often feel uncomfortable regardless of the thermostat setting. Smaller structures expose occupants to three, four or even six surfaces with the exterior exposed to the sun and hot outside air. More warm surfaces, more discomfort.

Cooler surfaces, more comfort

If you live in an under-insulated building and don’t mind using more electricity, you can set the thermostat lower. But if the mean radiant temperature is high, a 2 F (1.1 C) drop in air temperature will feel like only 1 F (0.6 C) — and those hot surfaces will still make you feel uncomfortable.

Adding insulation to your roof and replacing single-pane windows with double-pane units with low-emissivity (low-E) glass can help reduce the mean radiant temperature and your energy bills. They’re expensive improvements, but new federal tax credits and forthcoming rebates, to be administered by individual states, can help.

Trees, awnings and exterior shades can also reduce mean radiant temperatures by blocking direct sunlight. However, glass is a lousy insulator, so in very hot climates, single-pane windows completely protected from the sun can still become uncomfortably warm.

Adding a curtain inside — and keeping it closed — can help decrease mean radiant temperature because the curtain will be closer to the air temperature than the glass.

What about renters in old buildings?

Renters in older, under-insulated buildings are often less able to afford large energy bills, and landlords may be unable or unwilling to make expensive improvements. Making matters worse, older air conditioning systems use two to three times as much energy as newer units to deliver the same amount of cooling.

Since creating a comfortable operative temperature requires setting the thermostat lower, an HVAC system in an under-insulated building must work longer and harder, using more energy and further raising the cost. And the costs of discomfort are not only financial: Hot buildings also have adverse impacts on health and productivity.

Millions of Americans now live in places where cooling is the only thing preventing a mass casualty event. In Phoenix, city code requires rental units cooled by air conditioning to maintain a temperature of no more than 82 F (27.8 C), measured 3 feet above the floor in the center of the room. Unfortunately, the code does not specify whether 82 F is the operative temperature or the air temperature.

That one word makes a world of difference.

In an older, under-insulated building similar to my house — or, in what might be the worst-case scenario, a sun-fried southwest unit of the top floor of an uninsulated concrete high-rise — a seemingly safe air temperature of 82 F could easily mask dangerous operative temperatures of 96 F (35.6 C) or higher.

The key to better design

As a professor of architecture and building science, I believe today’s byzantine building codes and rental rules could be greatly improved for comfort by regulating mean radiant temperature rather than air temperature. Vast sections of code could be jettisoned by requiring that interior surfaces, which are easy to measure with an inexpensive infrared thermometer, be kept within a comfort range above 60 F (15.6 C) and below 85 F (29.4 C).

For more comfortable buildings, architects and engineers can apply simple, established principles, such as natural ventilation, shading and the right insulation and windows for the climate. Keeping heat out in the first place means we don’t have to spend so much on energy for cooling. Research shows that these measures can also make us safer by keeping buildings cooler for longer in summer power outages.

The happy result: homes and other buildings that are not only comfortable, but also safer and more affordable to operate.

Jonathan Bean, Associate Professor of Architecture, Sustainable Built Environments and Marketing, University of Arizona

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Television crime shows often are set in cities, but in its third season, ABC’s “American Crime” took a different tack. It opened on a tomato farm in North Carolina, where it showed a young woman being brutally raped in a field by her supervisor.

“People die all the time on that farm. Nobody cares. Women get raped, regular,” another character tells a police interrogator.

The show’s writers did their research. Studies show that 80% of Mexican and Mexican American women farmworkers in the U.S. have experienced some form of sexual harassment at work. Rape is common enough for some to nickname their workplace the “fields of panties.” For comparison, about 38% of women in the U.S. report experiencing some kind of workplace sexual harassment.

In a recent report, the U.N. Food and Agriculture Organization called for transformative changes to the formal and informal social systems that disempower women who work on farms and in the food sector around the world. While violence against women in agriculture may seem like an issue mainly experienced in developing countries, the truth is that it also happens all too often to women and girls on farms in the U.S.

As we see it, sexual exploitation perpetrated by men in positions of power instills fear that keeps farm laborers obedient, despite precarious working conditions – and keeps fruits and vegetables cheap.

Vulnerable workers

In our research on rural development, agriculture and rural gender inequality, we have found that gender-based violence against female workers is frighteningly common on U.S. farms.

According to the U.N., violence against women and girls includes “any gender-based act that creates sexual, psychological, or physical harm or suffering.” Men and boys can, of course, experience gender-based violence on U.S. farms, but to our knowledge no corroborating research exists.

Most often, sexual violence against women is committed by men in positions of power, such as foremen, farm labor contractors, farm owners and co-workers. Unfortunately, farm workers often buy into the myth that women bring sexual harassment on themselves. This belief makes it difficult for victims to get support.

Immigrant women farm workers are vulnerable because of power imbalances in their male-dominated workplaces. Women represent 28% of the nation’s farm workers, making them a minority on many farms. Most are immigrants from Latin America, and many are undocumented.

Female farm workers also face a gender wage gap of about 6%, partly because of parenting responsibilities that limit the number of hours they can work. Researchers have documented how men in positions of power take advantage of this vulnerability by offering hours and job perks in exchange for sexual favors and threatening to fire women if they refuse.

The role of child labor

Girls under the age of 18 are particularly vulnerable to sexual harassment and abuse on farms. While much-needed reporting has generated a public outcry against arduous work conditions for migrant child laborers, migrant children have worked in agriculture in the U.S. for decades – legally.

Agriculture holds a special status under federal labor laws, which permit farm owners to hire children as young as 12. Facing low wages and high poverty rates, farm worker families often rely on income from children’s work.

Experts say young girls may be especially vulnerable to sexual harassment and violence on farms because they are less likely to recognize and report abuse. Currently, children as young as 12 can be hired on farms without a cap on the number of hours they work, as long as they don’t miss school.

Democrats in Congress have repeatedly introduced versions of the Children’s Act for Responsible Employment and Farm Safety (CARE) Act since 2005. The bill would help address the vulnerability of young girls in farm work by aligning the legal farm working age with other industries.

Are guest worker visas the answer?

Since one major driver of the threat of violence against female farm workers is the fact that many of them are undocumented, could expanding the national H-2A agricultural guest worker visa program be a solution?

The H-2A program has exploded in popularity among farmers as a way to address agricultural labor shortages. The number of U.S. farm jobs certified for H-2A workers increased from 48,000 in 2005 to 371,000 in 2022 as farmers pressed Congress to allow more foreign nationals into the U.S. to fill temporary agricultural jobs.

This program, at least in theory, addresses several of the structural vulnerabilities of female farm workers. A visa confers a legal right to enter the country, alleviating the severe risk of sexual assault during clandestine border crossings. Legal status should also eliminate fear of deportation, which would bolster women’s courage to speak up against sexual violence in the workplace.

But the key word here is “should.”

Concerningly, migrant labor advocates have charged that the H-2A program promotes “systemic sex-based discrimination in hiring.” Only 3.3% of H-2A guest workers admitted in 2021 were women, a level that reflects historical trends. Some foreign advertisements for H-2A workers explicitly state that recruiters are looking for capable male workers.

When female farm workers are few in number, they have less collective capacity to protest or report sexually abusive conditions. Moreover, one 2020 report on labor conditions among H-2A workers found that 12% of participants – including women and men – had experienced sexual harassment. The authors believed this figure represented a gross undercount.

Guest worker visa programs can actually make workers more likely to tolerate abusive situations, because the workers’ legal status in the U.S. by definition is tied to their employment. Guest workers are often particularly fearful of employer retaliation if they complain about sexual abuse. In our view, guest worker visa programs institutionalize workers’ uncertain position instead of solving it.

A path forward

We agree with the U.N. that sweeping change is needed to empower women, raise farm productivity and promote human rights in the global food system. As U.S. lawmakers craft the next farm bill, they could do enormous good for women around the world by setting an example in American fields and farms.

As a first step, we believe lawmakers should pass the CARE Act, which would raise the legal working age on farms to 14, reducing the number of young girls who are vulnerable to abuse.

Second, legalizing the nation’s approximately 283,000 unauthorized farm workers would make those workers less vulnerable to sexual abuse by expanding employment opportunities outside of the agricultural sector.

Third, in our view, efforts to legalize farm workers – most recently through the Farm Workforce Modernization Act – should strengthen labor law enforcement and provide well-funded channels for reporting abuses and changing jobs when abuse occurs.

Bills proposing a pathway to legalization for agricultural workers have focused on providing enough labor for farm employers. For example, some proposals would expand the H-2A program and require workers already in the U.S. to continue working in agriculture for a number of years to receive a green card.

But without steps to improve labor protection systems, such changes could make workers even more vulnerable to sexual and other labor abuses, and have the counterproductive result of making them more likely to want to leave agriculture as soon as they can.

Kathleen Sexsmith, Assistant Professor of Rural Sociology, Penn State; Francisco Alfredo Reyes, Ph.D. Candidate in Rural Sociology & International Agriculture and Development, Penn State, and Megan A. M. Griffin, Student Community Engagement Specialist, Connecticut College

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The global childhood obesity epidemic has exploded. Over the past four decades, the world has witnessed a tenfold increase in obesity in children and adolescents between 5 and 19 years old.

More than 124 million children across the world are currently considered to be obese. In children under age 5, obesity used to be nearly unheard of. Now, more than 38 million young children live with this condition.

Researchers now estimate that there are more obese children than underweight children worldwide. Children and adolescents who are obese are more likely to become obese adults, setting them up for a lifelong trajectory of poor health.

With this growth in childhood obesity comes an increase in associated poor mental and physical health outcomes. Conditions that were once rare in children are now becoming increasingly common. These debilitating and costly diseases include hypertension, type 2 diabetes and others.

I am a public health researcher who studies and teaches about the factors underlying the obesity epidemic. My research seeks to understand what is driving these trends. Why are more and more people, including children, becoming obese?

Parsing the numbers

Childhood obesity was once predominantly an issue within developed nations. But it has become an emerging health concern even in the poorest countries and regions.

The standard measure used to determine obesity in children and adolescents has long been the body mass index, or BMI. This is a measure of an individual’s height as compared to their weight. Children whose BMI is a set threshold above the mean, or average, are considered obese. The role of BMI in defining obesity in children and adults may be changing, however.

Although BMI remains a low-cost and practical method for assessing obesity across populations – such as estimating the percentage of children in a particular nation who are obese – growing evidence has shed light on its limitations for use at the individual and clinical level. Leading medical organizations and researchers are encouraging physicians to consider the use of alternative measures, which may change the way children are screened for health risks related to their weight at the doctor’s office.

Critical role of parents and caregivers

In essence, childhood obesity is the result of kids eating and drinking more calories than they are burning off through play, movement and growth. Because of this, researchers have largely focused on understanding the individual eating and physical activity habits of these kids.

In the case of childhood obesity, researchers like me also know that parental figures play critical roles in both mirroring and creating opportunities for physical activity and healthy eating.

However, attempts to address childhood obesity have often focused excessively on individual behaviors of parents and children and too little on the environment where children and their families live. Research and statistics make it clear that this approach has failed and that new strategies are needed to understand and address why more children are becoming obese.

Social determinants of childhood obesity

Social determinants of health refer to the conditions where people live, learn, work, play and worship that affect health and quality of life.

The U.S. Department of Health and Human Services has described five broad categories of social determinants of health. These include:

• economic stability
• education access and quality
• health care access and quality
• neighborhood and the built environment, such as access to sidewalks and playgrounds
• social and community context

Social determinants can promote health. For example, neighborhoods with access to safe parks and green spaces and healthy food retailers may support healthy eating and physical activity for families.

But social determinants can also facilitate or encourage unhealthy behaviors. Because of their underlying role in contributing to health outcomes like childhood obesity, social determinants have been described as the “causes of the causes.” In other words, if poor diet is one of the causes of childhood obesity, then the social determinants that shape a child and their family’s food environment – such as lack of neighborhood grocery stores or limited income to purchase healthy foods – would be a cause of that poor diet.

Role of processed foods and physical inactivity

Globally, people are spending more time in cars and less time walking – one of the most basic forms of physical activity. Even in the poorest nations, private car ownership rates are skyrocketing. Kids who would inadvertently be engaging in physical activity just by walking or biking to school are more likely to be taking cars and buses to school instead.

When it comes to food, societies in the U.S. and around the world are producing and consuming more calorie-dense ultra-processed foods. Advertisers are targeting children with these food products and sugar-sweetened beverages online and on television.

But for working parents with long hours or those who are unable to afford healthy groceries, these are often the easiest or affordable options for feeding their children. In fact, poor families are more likely to live in communities designated as “food deserts,” areas where there are few or no grocery stores and a high concentration of fast-food restaurants and convenience stores.

And children’s lifestyles have changed drastically, shifting away from outdoor physical activity into an increasingly sedentary way of life, in large part due to social media and screen time. The role of screen time in the childhood obesity epidemic is a significant and growing area of concern and research.

In my own research in Peruvian communities, parents identified many of these same factors as barriers to their children being physically active. Mothers complained about the lack of safe spaces for their kids to play. Local parks were full of crime, and yards were congested with traffic and other safety hazards. Mothers felt it was safer for their young children to be inside watching TV than outside playing.

This example is not unique to Peru. Parents around the world are contending with these challenges.

Addressing the underlying causes

The field of public health prioritizes making the healthy choice the easy choice. Combating the childhood obesity epidemic means making healthy eating an easier choice for children and families than staying inside and eating processed foods.

However, the reality is that much of the world’s population now lives, works, plays and worships in places that make it more difficult to choose healthy behaviors.

Policies and programs that address the social determinants of health are a critical part of curbing the childhood obesity epidemic. These include investing in community resources like playgrounds and free programs that get kids outside.

Some nations and even U.S. cities have implemented “sin taxes” on sugar-sweetened beverages to discourage consumption. In Chile, policies have been created that limit television advertising of unhealthy food products toward children. Other policy examples include tax incentives and programs that increase access to healthy foods and lower their cost.

In my view, every kid should be able to swim in the safe and accessible community pool rather than relying on their living room TVs to escape the blistering summer heat, or access fresh and affordable produce in their neighborhood instead of having to rely on fast food as the only close food resource. Childhood obesity is a preventable condition that communities can reduce most effectively by increasing access to resources that will allow them to live healthy lives.

Kathleen Trejo Tello, Assistant Professor of Public Health, College of Charleston

This article is republished from The Conversation under a Creative Commons license. Read the original article.