In the last week the Ports of Long Beach and Los Angeles released their respective 2006 emissions inventory reports. <\/span>For Long Beach, emissions in 2006 were up slightly compared to 2005, but total cargo throughput was up by a greater percentage than emissions. <\/span>This means that emissions per unit of cargo are down at our port. <\/span>The story for Los Angeles is similar, but a bit more complicated: <\/span>emissions per unit of cargo are down for most pollutants, but up slightly or flat for others.<\/span><\/p>\n <\/span><\/p>\n First, a word or two about emissions inventories. <\/span>(And a warning that this post is kind of long, so you might want to get comfy with a cup of tea, or beverage of your choice, if you plan to stick with me.)<\/span><\/p>\n <\/span><\/p>\n Emissions, just to review the basics, are the gases and particles that come out of stacks, vents, and tailpipes. <\/span>In the case of the ports, there are five major types of emission sources: <\/span>ocean-going vessels, harbor craft such as tugboats, cargo-handling equipment within the terminals, railroad locomotives, and heavy-duty trucks. <\/span>The port emissions inventories include emissions from sources within the port, as well as some from port-related operations elsewhere in the South Coast Air Basin<\/font><\/a>, which includes much of the greater Los Angeles region.<\/span><\/p>\n <\/span><\/p>\n In an emissions inventory, pollutant emissions are quantified and totaled, typically in tons per year for port sources. <\/span>However, emissions are rarely directly measured. <\/span>This is because it’s technically difficult, time-consuming, and expensive to measure emissions, especially where mobile sources are concerned. <\/span>Instead, emissions are estimated – usually pretty accurately – using “emission factors.” <\/span>Emission factors are rates of emissions per unit of activity – such as grams of NOx per horsepower-hour – and they are derived by taking the average of published rates measured in various studies.<\/span><\/p>\n <\/span><\/p>\n To estimate, for example, total NOx emissions from cargo-handling equipment in the Port of Long Beach, you would need to know the emission factor for each type of equipment (crane, forklift, yard tractor, and so forth – about 20 types in all). <\/span>For each individual piece of equipment, you’d need to know its hours of operation, its rated horsepower, a load factor (since the equipment doesn’t operate at full capacity all the time), the age of the equipment (since emissions can increase as equipment deteriorates), whether it has any emission controls, what kind of fuel it used, and whether its engine had been replaced. <\/span>In the 2006 emissions inventory of cargo-handling equipment at Long Beach, 1,343 pieces of equipment from 31 different operations were inventoried. <\/span>Some of these pieces of equipment have hour meters that track their operating time, and some don’t. <\/span>Hours for the latter have to be tracked manually or estimated. <\/span>Believe me, I have simplified this explanation!<\/span><\/p>\n <\/span><\/p>\n The Port of Long Beach’s first published emissions inventory (in 2004) was for calendar year 2002; the second, for 2005, was released in 2007; and the year 2007 inventory is expected to be released by the end of this year, with regular annual updates coming after that. <\/span>This 2006 inventory is the first (though surely it will not be the last) to estimate emissions of key greenhouse gases, including carbon dioxide and methane. <\/span>In developing their emissions inventories, the ports and their consultants are guided by a technical working group that includes the U.S. Environmental Protection Agency, California Air Resources Board, and South Coast Air Quality Management District.<\/span><\/p>\n <\/span><\/p>\n In his remarks when releasing the inventory, Harbor Commission President Jim Hankla promised “brutal honesty” about the ports’ emissions. <\/span>I’d say the port lived up to that promise, since its press release this week bore the headline, “Inventory Shows Increase in Air Pollution.” <\/span>However, the subhead says “Reversal expected with Port initiatives to improve air quality.” <\/span>The year 2006 saw the highest-ever cargo throughputs, while the ports’ Clean Air Action Plan<\/font><\/a> was adopted in November of that year, so none of its programs were yet in effect. <\/span>In 2007, for example, the fleet of switching locomotives operated within the ports by Pacific Harbor Line began a complete turnover (finished this year) to meet current engine standards. <\/span>Some terminal operators switched to lower-sulfur fuel in vessels and other equipment in 2007. <\/span>However, specific CAAP programs – notably the Clean Truck Program – have proven complex to design and adopt, so their effects will not be seen even in 2007 emissions.<\/span><\/p>\n <\/span><\/p>\n What does the emissions inventory tell us about air quality in our city? <\/span>Before I answer that question, allow me one more technical explanation. <\/span>Air quality<\/u> refers to ambient levels or concentrations of pollution – what we experience where we live, work, and breathe. <\/span>Emissions<\/u> of pollutants – in grams or pounds or tons – reach the air by their various routes and then disperse at the whim of wind and weather and temperature, influenced by variations between day and night and among seasons. <\/span>Sometimes they even change into other substances while airborne. <\/span>So when we see an increase in port emissions – looking back at 2006 – we might generally expect to see a corresponding increase in local ambient pollution levels (keeping in mind that many other stationary and mobile sources of pollution are contributing). <\/span><\/span><\/p>\n <\/span><\/p>\n Both the Ports of Long Beach and Los Angeles monitor ambient air quality<\/font><\/a>, as does the South Coast Air Quality Management District. <\/span>The ports’ monitors measure ambient fine particles, as well as meteorological conditions. <\/span>A recent summary report on the Port of Los Angeles’ sites<\/font><\/a> shows that health-based air quality standards are exceeded on occasion, but does not show a clear pollution trend upward or downward over the most recent year (mid-2006 to mid-2007). <\/span>These monitors, like those operated by the air district nearby and elsewhere in the basin, will pick up any type of pollution, though they are intended to shed light on impacts related to port sources. <\/span>But it is difficult to definitively connect small changes in emissions with observed changes in air quality, especially at a single location.<\/span><\/p>\n