Another home hazard is the overuse of pesticides. People use pesticides to get rid of ants, cockroaches, and other insects. However, these chemicals can be hazardous for human beings. “If it is harmful to the bugs, it is also potentially harmful to us,” he says. Dr. Perez focuses on air particles that can set off problems in people’s lungs—especially asthma. Asthma is a condition when the airways become sore and swollen, making it hard to breath. It often can be aggravated by air pollutants. Dr. Perez works with the Philadelphia Housing Authority and the Department of Public Health. They evaluate air quality in homes and day-care centers and inform people about how to make their environment safer. They also help homeowners read labels to understand how to use pesticides safely. Sometimes, Dr. Perez and his colleagues spot other hazards in homes such as unlocked gates, ripped fences, and TVs that could easily tip, fall, and injure someone. They find household cleaning supplies—which have toxic chemicals— within reach of small children. If they see a carpet in bedrooms where children with asthma sleep, they will suggest removing it. Asthma-triggering chemicals can collect in carpets. One project Dr. Perez is working on with the Housing Authority encourages people to make their homes smoke-free. He not only helps people Hernando Perez, Ph.D. Making people think about the air indoors When asked to describe his job in one word, Dr. Hernando Perez says “necessary.” Dr. Perez is a professor who educates people about the hazards of indoor air pollution. Pollution can contaminate the environment in different ways. It can make water undrinkable. It can contaminate the soil so people can’t plant fruits and vegetables. It can even harm the air in your house. “Many environmental pollutants cause poor health and make us sick,” says Dr. Perez, who is an associate professor at Drexel University School of Public Health. “When we breathe in things that are unhealthy, we need to take steps to fix it,” he says. “I evaluate pollutants and then try to reduce the levels of pollutants.” Carbon monoxide is one type of dangerous chemical. It can build up in homes that don’t have proper ventilation. “It’s dangerous because you can’t smell it, hear it, feel it,” Dr. Perez says, “and it can be fatal.” 18