Air Pollution

Which of the following air pollutants is classified as a secondary pollutant?

A 52-year-old male resident of Delhi presents to the respiratory clinic with a 3-month history of progressive dyspnea, chronic cough, and wheezing. He works as a traffic policeman and has been stationed at a busy intersection for the past 8 years. His chest X-ray shows diffuse interstitial markings. Spirometry reveals FEV₁/FVC ratio of 65% with reduced FEV₁. He denies smoking and has no occupational exposure to asbestos or silica. The ambient air quality index (AQI) in his area averages 280 (very poor) with PM₂.₅ levels consistently above 150 µg/m³. Which pollutant is most likely responsible for his pulmonary pathology?

A 38-year-old woman from Mumbai presents with acute onset of severe dyspnea, chest tightness, and wheezing that began 2 hours after exposure to heavy smog during a traffic jam. She has a history of mild asthma (well-controlled on salbutamol PRN). On examination, peak expiratory flow (PEF) is 220 L/min (baseline 380 L/min), and diffuse bilateral wheezing is heard. Ambient air quality index is 380 (severe) with elevated ozone (O₃) levels of 180 µg/m³ and NO₂ levels of 95 µg/m³. Which air pollutant is most likely responsible for her acute asthma exacerbation?

A 52-year-old male resident of Delhi presents to the outpatient clinic with a 3-month history of progressive dyspnea on exertion, chronic cough with scanty sputum, and recurrent upper respiratory tract infections. He works as a traffic police officer and has been posted at a busy intersection for the past 8 years. On examination, he has mild cyanosis and barrel chest. Spirometry shows FEV₁/FVC ratio of 65% with reduced FEV₁. Chest X-ray reveals hyperinflation with flattened diaphragms. Which pollutant is most likely responsible for his chronic obstructive pulmonary disease?

A 38-year-old woman from Mumbai presents to the emergency department during a severe air pollution episode (AQI >400) with acute onset dyspnea, chest tightness, and wheezing. She has a history of mild asthma (controlled on salbutamol PRN). On examination, she has peak expiratory flow (PEF) of 220 L/min (baseline 380 L/min), oxygen saturation 91% on room air, and diffuse end-expiratory wheeze. Arterial blood gas shows pH 7.38, PaCO₂ 38 mmHg, PaO₂ 72 mmHg, HCO₃⁻ 22 mEq/L. Which air pollutant is most likely responsible for her acute asthma exacerbation during this pollution episode?