Maritime transport is an essential component of global trade, but it also contributes significantly to air pollution. Ships emit various gaseous and particulate pollutants, including CO2, SO2, NOx, soot, organic pollutants, and heavy metals. These emissions affect both environmental and human health, contributing to acid rain, smog formation, nutrient accumulation in ecosystems, climate change, and respiratory diseases. Understanding and monitoring these emissions is crucial for developing effective mitigation strategies.
The BSH Ship Emission Measurement Network
The German Federal Maritime and Hydrographic Agency (BSH) operates a dedicated ship emission measurement network to track air pollution from maritime sources. This network consists of stationary and mobile measurement stations strategically located near key shipping routes. The stations are positioned leeward of shipping lanes, within 2 km of vessel traffic, allowing for continuous 24/7 monitoring. The network uses state-of-the-art instrumentation to detect and analyze pollutants from passing ships, providing valuable data for regulatory compliance and scientific research.How Are Ship Emissions Measured?
The BSH network employs a combination of gas analyzers and particle measurement devices to assess ship emissions in real-time. The measurement stations are equipped with:- Gas analyzers to detect SO2, CO2, and NOx concentrations.
- Ultrafine particle measurement instruments, including the Fast Mobility Particle Sizer (FMPS) and Optical Particle Sizer (OPS), to measure particle number concentration and size distribution.
- Meteorological sensor and AIS receiver to allocate measured plumes to individual ships
- Near real-time data analysis to calculate ship individual emission factors for SOx, NOx and particles
- Automated reporting systems that send alerts if sulfur content in fuel exceeds regulatory limits.
The FMPS™ provides real-time measurement of ultrafine particle size distributions, capturing dynamic changes in ship exhaust plumes, while the OPS measures larger particles to give a comprehensive view of the emitted particulate matter. This monitoring approach enables the detection of emission trends over time. However, wind dependency remains a challenge, as it affects the ability to capture ship exhaust plumes accurately.
Fig 1: Measurement of particle size distribution shows clearly identifiable ship exhaust plumes in integral number concentration (top) and size-resolved (bottom) and different emission behavior for different ships recognizable (depending on engine type and fuel). Total particle counts by FMPS and OPS are indicated in blue and yellow (upper graph). The crossover between FMPS and OPS at particle size of 300 nm is indicated as black line (lower figure).
What Particle Sizes Do Ships Emit?
One of the main focuses of the BSH emission monitoring initiative is the measurement of ultrafine particles (UFPs), which are particularly relevant due to their impact on human health and the environment. Data collected from the measurement stations show that:- 90% of emitted particles are smaller than 80 nm.
- 50% of the particles are below 40 nm.
- 75% of particle mass originates from particles smaller than 200 nm.
From this finding it can be concluded that for effective reduction of ship-related air pollution, it is essential to address ultrafine particles, as they make up the majority of emissions.
Understanding the size distribution of emitted particles is crucial for evaluating their atmospheric lifetime, transport behavior, and potential health effects.
Key Takeaways
The findings from the BSH Ship Emission Measurement Network emphasize the need for continued ultrafine particle monitoring to better understand and mitigate the environmental impact of maritime transport. As regulations evolve, ongoing research and technological advancements will play a crucial role in reducing air pollution from shipping and improving air quality for coastal communities and beyond.
Learn More About Ambient Air Monitoring
The data was collected and kindly provided by the Federal Maritime and Hydrographic Agency (BSH).