Air Quality 4-2019

III. Air Quality


Substantial evidence supports a fair argument that the Draft Ordinance legalizing existing, and promoting unlimited new short-term vacation rentals (called “Homestays or Short-term rentals” by the Draft Ordinance) are a project thatmay have a significant impact on Air Quality.


CEQA Guidelines: III. AIR QUALITY— Where available, the significance criteria established by the applicable air quality management or air pollution control district may be relied upon to make the following determinations. Would the project:


  1. a) Conflict with or obstruct implementation of the applicable air quality plan?


  1. b) Violate any air quality standard or contribute substantially to an existing or projected air quality violation?


  1. c) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non- attainment under an applicable federal or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors)?


  1. d) Expose sensitive receptors to substantial pollutant concentrations?


  1. e) Create objectionable odors affecting a substantial number of people? N/A



Conclusion: The Significance Threshold is clearly exceeded by Greenhouse Gas Emissions from Tourists Staying in Homestay/STR’s, and Workers Forced in to Longer Commutes as Long-Term Housing is taken off the market.  The Significance threshold is already exceeded by homes taken off the long-term housing market through deliberate failure to enforce existing law, these conversions are made legal by the Draft Ordinance. The Draft Ordinance also encourages a massive increase on STR’s the  Draft Ordinance calls “Homestays” but are simply STR’s with room for one less person.  There is no limit on number or even density of Homestay STR’s.



In contrast the Consensus Position limits Homestay/Str’s to the numbers of bedrooms allowed by the Land Use Plans.  If limited to these numbers, the greenhouse gas emissions will be well below the Significance Threshold.



Evidence for, and Analysis of the Air Quality Impact of the Draft Ordinance


Greenhouse Gas Emissions from Tourists Staying in STR’s, and Workers Forced in to Longer Commutes as Long-Term Housing is Converted to STR’s and Homestays


Relevant Links:


10000 mT Greenhouse Gas Equivalencies Calculator | US EPA


Greenhouse Gas Equivalencies Calculator | US EPA


Monterey Air Thresholds DEIR_PLN130352_040115_CH4_S4-03


CO2 from 10 mile commute


US EPA CO2 emissions per mile



The Significance Threshold for Greenhouse Gas Emissions in Monterey County is 10,000 Metric Tons of Carbon Dioxide and equivalents.


There are two possible approaches to determine if the Status Quo and/or Draft Ordinance exceed this threshold:


  1. Number of vehicles from tourists staying in STR’s


  1. Additional Driving by Workers forced to find housing further from their jobs



Cars Driven by Tourists Staying in STR’s


The County as a whole including the Cities (July 2018) had 2,073 listings that fit the STR definition – with a total of 4,478 rooms for rent.[1]


Using the July 2018 data, assuming one car per room that equals 4,476 vehicles.  Assuming STRs continue to expand at 30% or more per year (the current rate of expansion), by 2020 there will be over 5,000 vehicles.


CO2 per year for a car is 4.6 metric tons

at 100% capacity factor = 23,000 metric tons/year

at 71% capacity factor = 16,330 metric tons/year


Significance Threshold = 10,000 metric tons/year[2]


Greenhouse gas emissions are over the Significance Threshold.



Increased Commutes by Workers


Many complaints about increased commutes are made by workers forced to live farther from their jobs.  Over 400 people per day commute to Bug Sur –  a commute of over 50 miles each way for many.  Many people who work in Monterey have been forced to move in to the Salinas area – an additional commute of 10 to 20 miles each way.


There are more than 70,000 people who commute to work from apartments.  For every 5 miles each way they have to commute, greenhouse gas emissions are:


10 miles per day x

70,000 vehicles x

200 days per year x

0.89 pounds of CO2 (404 grams) per mile[3]

= 56,519 MT    (note – there are 2,204.62 pounds per Metric ton)



Greenhouse gas emissions are over the

Significance Threshold



  • Monterey County Total Numbers of STR’s, and Bedrooms for Rent in STR’s
  • Figures vary from different sources, but the contractor to Monterey County found 799 advertised rentals in January 2018.[4]There are a little over 2 bedrooms rented per site,[5]and an average of slightly over 2 people per room.[6]
  • In July 2018 there were 1,726 rooms for rent in Monterey County – the vast majority on the coast and in Carmel Valley.In May 2019 there are between 3,000 and 6,000.
  • And this vastly understates the total impact of STR on Monterey County because these figures are for the Unincorporated area only.
  • The County as a whole including the Cities (July 2018) had 2,073 listings that fit the STR definition – with a total of 4,478 rooms for rent.[7][These tourists, although they may be sleeping at their rooms in Pacific Grove, Seaside, Marina or other City, go to the same places tourists who stay in hotels go.  Big Sur and Point Lobos are two of the prime tourist destinations in the world.  By March of 2019 this increased to 2,425 (5,238 rooms for rent).[8]




[2]County of Monterey Section 4.3. Air Quality and Greenhouse Gas Emissions

Generate greenhouse gas emissions, either directly or indirectly, that may have a  significant impact on the environment; and/or conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases.    The 2014 CEQA Guidelines do not establish a quantitative threshold of significance for GHG impacts; instead, lead agencies have the discretion to establish such thresholds for their respective jurisdictions. In Monterey County, the Greenhouse Gas Thresholds and Supporting Evidence prepared by the San Luis Obispo County Air Pollution Control District (SLOAPCD) in 2012 is typically used as a guideline for evaluating GHG emissions for CEQA documents within Monterey County (MBUAPCD 2014). The threshold established by the SLOAPCD is 10,000 metric tons (MT)/year for stationary sources, or 1,150 MT/year or 4.9 MT Service Population (SP)/year (residents +employees). This stationary source threshold is consistent with the threshold established by the BAAQMD, the Sacramento Metropolitan Air Quality Management  District, and Santa Barbara County standards.


Therefore, a proposed project would have a significant impact related to GHG emissions if the project would:

  • Generate more than 10,000 MT of equivalent carbon dioxide (CO2e) per year; or
  • Generate 4.9 MT SP per year.

It should be noted that no air district has the power to establish definitive thresholds that will completely relieve a lead agency of the obligation to determine significance on a case-by-case basis (South Coast Air Quality Management District [SCAQMD] 2008). Additionally, SLOAPCD requires that construction emission of a project be amortized over the life of a project and added to the operational emissions.

[3]US EPA CO2 emissions per mile


[4]Host Compliance Report, Monterey County Planning Commission Agenda Item No. 2; Legistar File Number: PC 18-009; REF100042/REF130043 – SHORT-TERM RENTAL CODE COMPLIANCE: January 31, 2018;

[5]The actual number of rooms per STR is 2.16;

[6]The actual number of people per room per STR is 2.42;



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