Question

California was in the news during January of 2014 due to exceptional drought conditions and unusually warm and calm days during what is normally their rainy and windy season. The graphic below shows the AQI (air quality index) for January 22, 2014 for the California region. Nitrogen dioxide concentration in the air is a contributing factor in the calculation of the AQI. Select the statements from the list below that explain how NO2 (g) could have contributed to the poor AQI in the region. Dry air allows NO2 to accumulate in the atmosphere. Stagnant air allows NO2 to accumulate in the atmosphere. Rain has no effect on NO2 in the atmosphere. Decreased use of cars and trucks produces more NO2 that can accumulate in the atmosphere.

Answer 1

Stagnant and dry air both contribute to the accumulation of NO2 in the atmosphere, worsening air quality and AQI levels. Vehicle emissions are a major source of NO2, and decreased use does not lead to an increase in NO2 levels.

Step-by-step explanation:

Nitrogen dioxide (NO2) is a significant air pollutant that contributes to poor air quality conditions, such as those experienced in California during January 2014. Factors affecting NO2 levels include the climate and human activities. The statement that stagnant air allows NO2 to accumulate in the atmosphere is correct because in the absence of wind, pollutants like NO2 can build up more readily near the ground, worsening AQI levels. Similarly, the statement that dry air allows NO2 to accumulate in the atmosphere is also correct as rain can help remove pollutants from the air, a process known as 'wet deposition.' Thus, the lack of rain would contribute to the accumulation of NO2. However, decreased use of cars and trucks does not produce more NO2; in fact, it would likely lead to a decrease in NO2 levels since vehicle emissions are a major source of NO2.

NO2 and other nitrogen oxides (NOx) contribute to the formation of ground-level ozone, fine particle pollution, and can be transported long distances by winds, affecting both outdoor and indoor air quality. They are also responsible for the hazy conditions that impair visibility in many national parks. Therefore, the increase in NO2 levels due to stagnant air and lack of rain during California's drought likely contributed to the poor AQI reported in the region.