Ambient Air Sampling Techniques

• This document is a summary of ambient air sampling, from introduction to measurment techniques.

Introduction to Ambient Air Sampling

• Ambient air sampling is collecting and analyzing air samples from the environment to assess air quality.
• Air sampling helps understand pollution levels, identify sources, and implement measures to improve air quality and protect public health.

Objectives of Air Sampling

• Determine Contaminant Concentrations: identify and quantify pollutants in the air.
• Evaluate Control Measures: assess the effectiveness of pollution control methods.
• Regulatory Compliance: ensure adherence to environmental and occupational health standards.

Overview of Sampling Techniques

• Passive Sampling: pollutants diffuse through a barrier and are collected by an absorbent material.
• Passive sampling advantages: low cost, low maintenance, no power supply needed.
• Passive sampling disadvantages: requires long sampling periods, limited to pollutants with known diffusion rates.
• Active Sampling: uses mechanical devices to draw air into a sampler where pollutants are collected for analysis.
• Active sampling advantages: precise control of air volume, effective for low concentrations, real-time monitoring.
• Active sampling disadvantages: Requires power, regular maintenance, and is more expensive than passive sampling.
• Grab Sampling: A single air sample is collected at a specific time and place for analysis.
• Grab sampling advantages: simple and cost-effective.
• Grab sampling disadvantages: provides only a snapshot and may not represent long-term conditions.
• Continuous Monitoring: uses sensors to collect real-time air quality data.
• Continuous monitoring advantages: immediate detection of changes, ensures regulatory compliance.
• Continuous monitoring disadvantages: requires reliable sensors, costly setup and maintenance.

Overview of Sampling Equipment

• Respirable Dust Samplers: measure airborne particles small enough to reach the lungs.
• Respirable dust samplers are used in industrial hygiene and environmental monitoring.
• Filter Papers are made from cellulose fibers to trap particles
• Filter papers are used for air pollution analysis and sample preparation.

Common Air Pollutants and Their Health Effects

• Particulate Matter (PM) causes respiratory and cardiovascular diseases.
• Sulfur Dioxide (SO2) is produced from burning fossil fuels, affects asthma patients and can cause lung diseases.
• Nitrogen Dioxide (NO2) is emitted from vehicles and industries, reduces lung function and increases respiratory infections.
• Carbon Monoxide (CO) is a colorless, odorless gas from incomplete fuel combustion; can be fatal due to oxygen deprivation.

Measurement Techniques

• Particulate Matter (PM) is measured with: Gravimetric Sampling (weighing particles on filters), Optical Particle Counters (OPC), Beta Attenuation Monitoring (BAM).
• Sulfur Dioxide (SO2) is measured with: Spectrophotometry, Electrochemical Sensors.
• Nitrogen Dioxide (NO2) is measured with: Chemiluminescence, Diffusion Tubes, Electrochemical Sensors.
• Carbon Monoxide (CO) measured with: Electrochemical Sensors, Non-Dispersive Infrared (NDIR) Spectroscopy.