Item6Item 6Over the past 40 years, air quality has gotten substantially worse in many of the major cities of North America.Group startsTrue or FalseTrue, unselectedFalse, unselected

How many chemicals can affect indoor air quality?Group of answer choicesBillionsThousandsMillionsHundreds

Multiple Choice QuestionWhat is the most common level of air quality found in areas where people live?Multiple choice question.The air is contaminated to some degree.Air pollution is the worst it has been in human history.The air is free of pollution.

Multiple Choice QuestionThe air pollution problems in what major city are so bad that visibility is commonly only a few hundred meters and most days are considered either unhealthy or hazardous in terms of an air pollution index?Multiple choice question.Los Angeles, CaliforniaLondon, EnglandBeijing, ChinaMoscow, Russia

Indoor air pollution is considered one of the most serious problems in developed countries because

True or False QuestionTrue or false: Indoor air pollution is often higher than it is outdoors.True false question.TrueFalse