Question 1: Define 'particulates' in the context of atmospheric pollution.

Answer: Particulates are tiny solid or liquid particles suspended in the air, originating from various natural and human activities, that can contribute to air pollution.

Question 2: List three common sources of atmospheric particulates.

Answer: Vehicle exhaust emissions, industrial processes, and combustion of fossil fuels such as coal and petrol.

Question 3: Explain how particulates can affect human health.

Answer: Particulates can be inhaled into the lungs, causing respiratory problems, cardiovascular diseases, and aggravating conditions like asthma. Fine particles can penetrate deep into lung tissue and even enter the bloodstream, leading to serious health issues.

Question 4: Which size range best describes fine particulate matter (PM2.5)?

Answer: Particles smaller than 2.5 micrometres

Question 5: Fill in the blank: Particulates with a diameter less than ____ micrometres are classified as PM2.5.

Answer: 2.5

Question 6: Describe a simple experimental method to measure the concentration of particulates in the air.

Answer: One method involves using a filter sampler that draws air through a filter paper over a set period. The filter is then weighed to determine the mass of particulates collected, which can be used to calculate concentration based on airflow volume.

Question 7: Calculate the mass concentration (μg/m³) of particulates if a 10 cm by 10 cm filter collects 50 mg of particles after drawing 1000 litres of air.

Answer: Mass concentration = (mass of particles in μg) / (volume of air in m³) Mass of particles = 50 mg = 50,000 μg Volume of air = 1000 litres = 1 m³ Concentration = 50,000 μg / 1 m³ = 50,000 μg/m³

Question 8: Identify two safety precautions to consider during particulate sampling experiments.

Answer: Use appropriate personal protective equipment (PPE) such as masks and gloves, and ensure proper ventilation to avoid inhaling or contaminating with hazardous particles.

Question 9: Analyse the potential environmental impact of high levels of atmospheric particulates in urban areas.

Answer: High levels of atmospheric particulates can reduce air quality, leading to health problems in residents. They can also cause environmental issues such as reduced visibility, damage to ecosystems, and contribute to acid rain and climate change by affecting atmospheric radiation balance.

Question 10: Explain how catalytic converters in vehicles help reduce particulate emissions.

Answer: Catalytic converters facilitate chemical reactions that convert harmful pollutants, including some particulates and gaseous emissions, into less harmful substances such as carbon dioxide, nitrogen, and water vapour, thereby reducing overall particulate emissions.