Qualities or contaminants of living and working surroundings that contribute to health and health care disparities such as poor air quality, crime, contaminated water, and exposure to toxic chemicals. For example, population differences in the incidence of asthma may be due, in part, to differences in exposure to chemicals that cause certain allergies. They may also be due, in part, to the lack of exposure to certain germs when children are young. If environments are different for different groups of individuals, sometimes their health will be different too. Environmental differences may be an important reason for health disparities. They may also be an important reason for health care disparities if, for example, people living in high crime areas are too afraid to travel to the doctor or hospital and so don't get the same care as people who live in safer neighborhoods. Environmental factors in combination with individual, social and health system factors lead to health and healthcare disparities.